What you need to do to add signals to your module: a primer
Version 1.00
HUB Signaling Committee
June 12, 2013
The goal of this document is provide a straightforward and hopefully simple recipe for what a HUB
module group member needs to do to add signaling to their module. The signal committee has worked
on this project for over 2 years now and has provided a roadmap. In any project such as this some
decisions and compromises had to be made that affect all how the goal of signaling a modular railroad
can be accomplished. This document will do its best to provide module members with the list of what is
needed, what things must be done, what things should not be done and links to resources on the
internet and our webpage to help. In addition, members of signal committee can be contacted for help
and advice. The term “active” module will be used to describe a module with signaling capability.
1. Required Hardware: This list does depend, in part, on the track plan but can be addressed even
without a track plan. The necessary hardware list is:
a. A C/MRI SuperMini Board (SMini) [HUB gets discounts on these] One of these will
usually be sufficient for a single 2x4 ft module.
b. A 5vDC regulated power supply to power the SMini Board [HUB has these available for
members]
c. Replacement Terminal Strips (two required) for the wiring harness [See Diagram X]
d. As many C/RMI DCCOD occupancy detectors are needed for both the inner and out
mainlines [HUB gets a discount on these as well]
e. A 12 vDC power supply to (does not need to be regulated) to power the DCCODs.
f. As many Common Anode signals as required by the track plan. [Many vendors]
2. Required Software: A single CATS/JMRI file created by a tool called the CATS Designer. This
graphic tool describes the physical track plan and all of the devices, detectors, blocks, SMINI
boards, occupancy detectors, DCC controlled turnouts, turnout positions and signals contained
on the module. At the outset, members of the signal committee will take on this task with the
members until many members have become proficient with software.
3. Required Permissions: You will need two permissions from the Modular Superintendent.
a. An assigned Address for the SMini Board
b. Assignment of Accessory Decoder addresses for Tortoises
4. The Wiring: With either a new passive or a current existing passive module, the outer main was
wired to the red/black terminal pair, the inner main from the yellow/black terminal pair and
third track from the blue/black terminal pair. Active modules have a different wiring and, of
course, require segmenting the track into separately detectable blocks. Two rules: 1) Signal
gaps only require gapping the outer rail (red/pink/yellow,grey or blue) but DCC booster gaps
(which may occur at a signal gap) require double gapping. Furthermore, modules need to have
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the capacity to can communicate their occupancy information to the two modules flank an
active module on either side. The tracks that abut the joiner tracks are referred to as “end track
segments” and those that are between end track segments as “intervening segments.”
a. Outer Main: Consider an eastbound train travelling on the outer main will enter from
the west. The first track segment it will come upon is the west end track segment. This
track segment is powered from left hand red/black pair from coming from the module
the active module’s left. Both power and occupancy information are on those wires. As
the train proceeds easterly, it will encounter one or more intervening segments. These
are wired from pink/black terminals and each segment must provide its own DCCOD to
determine occupancy. In diagram 2 below, the example shows 2 such track segments.
The last track the train will encounter before hitting the east end joiner track is the East
end segment. This segment is also powered from pink/black pair and also has its own
DCCOD. However, the wire to this track segment feeds the red terminal on the right
hand side of second terminal strip. This provides both power and occupancy
information to the module to the active modules right. This is how we get power and
more importantly occupancy information from unaltered existing passive modules. [See
Diagrams 1-5 below]
b. Inner Main: The situation is the same for the inner main but the color of the terminals
is different. A Westbound train travelling on the inner main will enter from the east.
The first track segment it will come upon is the east end track segment. This track
segment is powered from right hand yellow/black pair from coming from the module
the active module’s left. Both power and occupancy information are on those wires. As
the train proceeds easterly, it will encounter one or more intervening segments. In
diagram 3 below, the example shows 2 such track segments. These are wired from
grey/black terminals and each segment must provide its own DCCOD to determine
occupancy. The last track the train will encounter before hitting the west end joiner
track is the West end segment. This segment is also powered from grey/black pair and
also has its own DCCOD. However, the wire to this track segment feeds the yellow
terminal on the left hand side of first terminal strip. This provides both power and
occupancy information to the module to the active module’s left. [See Diagrams 1-5
below]
c. Third Track: The third track is powered as before using the blue/black pair. Module
owners can choose to add occupancy to third track blocks at their discretion but
occupancy detection on the third track is entirely optional. One important rule
regarding third track. No occupancy information can be passed to an adjoining module
on either side across the joiner track. Another way of stating this is that the end
segments on third tracks must not have DCCODs on them.
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Diagram 1: Module with joiner tracks and “passive end segments” only
Diagram 2: Module outer main with passive end segments and intervening segments
Diagram 3: Module both mains with passive end segments and intervening segments
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Diagram 4: Module both mains all track segments shown
Diagram 5: Wiring Schematic for Inner and Outer Mains
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Figure 6 Terminal Strip Conventions
5. Signals: A common anode signal capable of showing three red, yellow and green will have three
separate LEDs, one for each color [Diagram 6]. Such a signal will have 4 wires per signal head,
one for each color plus one for the common anode. This will work whether the LEDs are
arranged vertically as in a D-type signal, in a triangular arrangement as in a G-type signal or all in
the same housing as in a searchlight signal [Diagram 7]. The key thing to note is that common
anode signals will all have 4 wire, one per colon and a common anode.
Signal Sources: The table below provides some sources for signals
Website
Vendor
BLMA
http://www.blmamodels.com
Custom Signal Systems:
http://www.customsignalsystems.com/
Integrated Signal Systems:
http://www.integratedsignalsystems.com/
NJ International:
http://www.njinternational.com/
Oregon Rail Systems:
http://www.oregonrail.com/
South Bend Signal Company:
http://www.sbsignal.com/
Tomar:
http://www.sbsignal.com/
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Diagram 7: Wiring for a common anode three light signal
Diagram 8: Different Signal Heads but Each has 4 Wires and a Common Anode (+5vDC)
D-Type
G-Type
Searchlight
Signal placement: While this can be a long discussion, here are a couple of guidelines from the
Masters at the 74th NMRA Convention in Milwaukee.
1. All entrances to the main lines should be protected by a signal. This equates to
having 3 signals around all turnouts and is often referred to as an OS section.
[Diagram 9] You can think of this as a triangle around each frog.
Diagram 9: Triangular Configuration of an OS Section
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2. Mike Burgett, who is an executive at in charge of signals for the CP, showed diagram
10 below as a guide to physical placement of signal masts. Recommended
prototypical placement is at least 16 ft beyond the clearance point and 40 ft in front
of the points.
Diagram 10. Signal Placement
6. Turnouts: There are a few key points to remember with turnouts.
a. It is increasingly important that mainline turnouts are controllable by accessory DCC decoders.
Additionally, it is critical that mainline turnouts provide feedback to the dispatcher panel telling
the point position. Fortunately this is easy with Tortoise or Cobalt powered motors. You just
use one of the sets of switches included in the turnout motors. The center pole connects to
signal ground and one of the other poles connects to a CMRI input pin. This will provide on and
off information which can be equated to straight or diverting position of the points.
b. There are now 3 different methods to throw a turnout: 1) from a control panel, 2) from a panel
and from the dispatcher’s panel. With signaling it is important that all three of these methods
remain in synch. This is one of the challenges of setting up and wiring turnouts on active
modules. Clearly all three methods don’t have to be employed. For example, you could omit a
physical panel. However, you cannot ignore throws from a throttle or throws from the
dispatcher panel.
c. Most commercially available DCC accessory decoders provide a method for connecting
pushbuttons for panel control – take advantage of them. Consider panels such as those on
Upton yard or Tipple.
d. Powered Frogs: Be careful powering your frogs. It is important that the power for the frog
come from the same block that encloses the turnout. The train will operate fine with any source
of the power but if that power comes from another block it will appear occupied when a train
hits the frog. This is something you definitely don’t want.
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